class LlvmAT4 < Formula
  desc "Next-gen compiler infrastructure"
  homepage "https://llvm.org/"
  url "https://releases.llvm.org/4.0.1/llvm-4.0.1.src.tar.xz"
  sha256 "da783db1f82d516791179fe103c71706046561f7972b18f0049242dee6712b51"
  revision 1

  bottle do
    cellar :any
    sha256 "d9a4baa88b775e4fb640532b08d1aa290ab7a606683cd3e40a8afedb7f502bbf" => :mojave
    sha256 "ee8df6a837856170a8e4acd2be96bda6bbb3a17901491c1f0a8cc3da391254aa" => :high_sierra
    sha256 "b9f1d2ba25ebe94dd48e7ecbbb7d83f657b435f9a3a4c8aed9e55936fc7ae9ef" => :sierra
  end

  keg_only :versioned_formula

  depends_on "cmake" => :build
  depends_on "libffi"
  depends_on "python@2" if MacOS.version <= :snow_leopard

  # According to the official llvm readme, GCC 4.7+ is required
  fails_with :gcc_4_0
  fails_with :gcc_4_2
  ("4.3".."4.6").each do |n|
    fails_with :gcc => n
  end

  resource "clang" do
    url "https://releases.llvm.org/4.0.1/cfe-4.0.1.src.tar.xz"
    sha256 "61738a735852c23c3bdbe52d035488cdb2083013f384d67c1ba36fabebd8769b"
  end

  resource "clang-extra-tools" do
    url "https://releases.llvm.org/4.0.1/clang-tools-extra-4.0.1.src.tar.xz"
    sha256 "35d1e64efc108076acbe7392566a52c35df9ec19778eb9eb12245fc7d8b915b6"
  end

  resource "compiler-rt" do
    url "https://releases.llvm.org/4.0.1/compiler-rt-4.0.1.src.tar.xz"
    sha256 "a3c87794334887b93b7a766c507244a7cdcce1d48b2e9249fc9a94f2c3beb440"
  end

  resource "libcxx" do
    url "https://releases.llvm.org/4.0.1/libcxx-4.0.1.src.tar.xz"
    sha256 "520a1171f272c9ff82f324d5d89accadcec9bc9f3c78de11f5575cdb99accc4c"
  end

  resource "libunwind" do
    url "https://releases.llvm.org/4.0.1/libunwind-4.0.1.src.tar.xz"
    sha256 "3b072e33b764b4f9b5172698e080886d1f4d606531ab227772a7fc08d6a92555"
  end

  resource "lld" do
    url "https://releases.llvm.org/4.0.1/lld-4.0.1.src.tar.xz"
    sha256 "63ce10e533276ca353941ce5ab5cc8e8dcd99dbdd9c4fa49f344a212f29d36ed"
  end

  resource "lldb" do
    url "https://releases.llvm.org/4.0.1/lldb-4.0.1.src.tar.xz"
    sha256 "8432d2dfd86044a0fc21713e0b5c1d98e1d8aad863cf67562879f47f841ac47b"
  end

  resource "openmp" do
    url "https://releases.llvm.org/4.0.1/openmp-4.0.1.src.tar.xz"
    sha256 "ec693b170e0600daa7b372240a06e66341ace790d89eaf4a843e8d56d5f4ada4"
  end

  resource "polly" do
    url "https://releases.llvm.org/4.0.1/polly-4.0.1.src.tar.xz"
    sha256 "b443bb9617d776a7d05970e5818aa49aa2adfb2670047be8e9f242f58e84f01a"
  end

  def install
    # Apple's libstdc++ is too old to build LLVM
    ENV.libcxx if ENV.compiler == :clang

    (buildpath/"tools/clang").install resource("clang")
    (buildpath/"tools/clang/tools/extra").install resource("clang-extra-tools")
    (buildpath/"projects/openmp").install resource("openmp")
    (buildpath/"projects/libcxx").install resource("libcxx")
    (buildpath/"projects/libunwind").install resource("libunwind")
    (buildpath/"tools/lld").install resource("lld")
    (buildpath/"tools/polly").install resource("polly")
    (buildpath/"projects/compiler-rt").install resource("compiler-rt")

    # compiler-rt has some iOS simulator features that require i386 symbols
    # I'm assuming the rest of clang needs support too for 32-bit compilation
    # to work correctly, but if not, perhaps universal binaries could be
    # limited to compiler-rt. llvm makes this somewhat easier because compiler-rt
    # can almost be treated as an entirely different build from llvm.
    ENV.permit_arch_flags

    args = %W[
      -DLIBOMP_ARCH=x86_64
      -DLINK_POLLY_INTO_TOOLS=ON
      -DLLVM_BUILD_EXTERNAL_COMPILER_RT=ON
      -DLLVM_BUILD_LLVM_DYLIB=ON
      -DLLVM_ENABLE_EH=ON
      -DLLVM_ENABLE_FFI=ON
      -DLLVM_ENABLE_LIBCXX=ON
      -DLLVM_ENABLE_RTTI=ON
      -DLLVM_INCLUDE_DOCS=OFF
      -DLLVM_INSTALL_UTILS=ON
      -DLLVM_OPTIMIZED_TABLEGEN=ON
      -DLLVM_TARGETS_TO_BUILD=all
      -DWITH_POLLY=ON
      -DFFI_INCLUDE_DIR=#{Formula["libffi"].opt_lib}/libffi-#{Formula["libffi"].version}/include
      -DFFI_LIBRARY_DIR=#{Formula["libffi"].opt_lib}
      -DLLVM_CREATE_XCODE_TOOLCHAIN=ON
    ]

    mkdir "build" do
      system "cmake", "-G", "Unix Makefiles", "..", *(std_cmake_args + args)
      system "make"
      system "make", "install"
      system "make", "install-xcode-toolchain"
    end

    (share/"clang/tools").install Dir["tools/clang/tools/scan-{build,view}"]
    (share/"cmake").install "cmake/modules"
    inreplace "#{share}/clang/tools/scan-build/bin/scan-build", "$RealBin/bin/clang", "#{bin}/clang"
    bin.install_symlink share/"clang/tools/scan-build/bin/scan-build", share/"clang/tools/scan-view/bin/scan-view"
    man1.install_symlink share/"clang/tools/scan-build/man/scan-build.1"

    # install llvm python bindings
    (lib/"python2.7/site-packages").install buildpath/"bindings/python/llvm"
    (lib/"python2.7/site-packages").install buildpath/"tools/clang/bindings/python/clang"
  end

  def caveats; <<~EOS
    To use the bundled libc++ please add the following LDFLAGS:
      LDFLAGS="-L#{opt_lib} -Wl,-rpath,#{opt_lib}"
  EOS
  end

  test do
    assert_equal prefix.to_s, shell_output("#{bin}/llvm-config --prefix").chomp

    (testpath/"omptest.c").write <<~EOS
      #include <stdlib.h>
      #include <stdio.h>
      #include <omp.h>

      int main() {
          #pragma omp parallel num_threads(4)
          {
            printf("Hello from thread %d, nthreads %d\\n", omp_get_thread_num(), omp_get_num_threads());
          }
          return EXIT_SUCCESS;
      }
    EOS

    system "#{bin}/clang", "-L#{lib}", "-fopenmp", "-nobuiltininc",
                           "-I#{lib}/clang/#{version}/include",
                           "omptest.c", "-o", "omptest"
    testresult = shell_output("./omptest")

    sorted_testresult = testresult.split("\n").sort.join("\n")
    expected_result = <<~EOS
      Hello from thread 0, nthreads 4
      Hello from thread 1, nthreads 4
      Hello from thread 2, nthreads 4
      Hello from thread 3, nthreads 4
    EOS
    assert_equal expected_result.strip, sorted_testresult.strip

    (testpath/"test.c").write <<~EOS
      #include <stdio.h>

      int main()
      {
        printf("Hello World!\\n");
        return 0;
      }
    EOS

    (testpath/"test.cpp").write <<~EOS
      #include <iostream>

      int main()
      {
        std::cout << "Hello World!" << std::endl;
        return 0;
      }
    EOS

    # Testing Command Line Tools
    if MacOS::CLT.installed?
      libclangclt = Dir["/Library/Developer/CommandLineTools/usr/lib/clang/#{MacOS::CLT.version.to_i}*"].last { |f| File.directory? f }

      system "#{bin}/clang++", "-v", "-nostdinc",
              "-I/Library/Developer/CommandLineTools/usr/include/c++/v1",
              "-I#{libclangclt}/include",
              "-I/usr/include", # need it because /Library/.../usr/include/c++/v1/iosfwd refers to <wchar.h>, which CLT installs to /usr/include
              "test.cpp", "-o", "testCLT++"
      assert_includes MachO::Tools.dylibs("testCLT++"), "/usr/lib/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./testCLT++").chomp

      system "#{bin}/clang", "-v", "-nostdinc",
              "-I/usr/include", # this is where CLT installs stdio.h
              "test.c", "-o", "testCLT"
      assert_equal "Hello World!", shell_output("./testCLT").chomp
    end

    # Testing Xcode
    if MacOS::Xcode.installed?
      libclangxc = Dir["#{MacOS::Xcode.toolchain_path}/usr/lib/clang/#{DevelopmentTools.clang_version}*"].last { |f| File.directory? f }

      system "#{bin}/clang++", "-v", "-nostdinc",
              "-I#{MacOS::Xcode.toolchain_path}/usr/include/c++/v1",
              "-I#{libclangxc}/include",
              "-I#{MacOS.sdk_path}/usr/include",
              "test.cpp", "-o", "testXC++"
      assert_includes MachO::Tools.dylibs("testXC++"), "/usr/lib/libc++.1.dylib"
      assert_equal "Hello World!", shell_output("./testXC++").chomp

      system "#{bin}/clang", "-v", "-nostdinc",
              "-I#{MacOS.sdk_path}/usr/include",
              "test.c", "-o", "testXC"
      assert_equal "Hello World!", shell_output("./testXC").chomp
    end

    # link against installed libc++
    # related to https://github.com/Homebrew/legacy-homebrew/issues/47149
    system "#{bin}/clang++", "-v", "-nostdinc",
            "-std=c++11", "-stdlib=libc++",
            "-I#{MacOS::Xcode.toolchain_path}/usr/include/c++/v1",
            "-I#{libclangxc}/include",
            "-I#{MacOS.sdk_path}/usr/include",
            "-L#{lib}",
            "-Wl,-rpath,#{lib}", "test.cpp", "-o", "test"
    assert_includes MachO::Tools.dylibs("test"), "#{opt_lib}/libc++.1.dylib"
    assert_equal "Hello World!", shell_output("./test").chomp
  end
end
